Seed Row Tolerance of 16-20-0-13 and 12-40-0-6.5S-1Zn in Western Canada

The majority of phosphorus (P)-based fertilizers are either applied directly in the seed furrow (seed row) or side banded close to the seed row, for the growing of small grain cereals, canola, and lentils in the western Prairie Provinces of Canada. Improved crop genetics have resulted in increased crop yield potentials, and accompanying increased removals of P in harvested grain. Farmers want to increase seed row P applications but information is lacking as to whether crop stands and yields may decrease at the higher seed row P application rates. A research study assessing the effect of low and elevated application rates of 16-20-0-13 sulfur (S) and 12-40-0-6.5S-1 zinc (Zn) compared to monoammonium phosphate (MAP) placed in the seed rows of spring wheat, canola, and lentils was continued with a regional research association (Farming Smarter) near Lethbridge, Alberta. During the crop seasons of 2015 and 2016, the research was conducted by a different private third-party research group, assessing seed row fertilizer effects on both canola and spring wheat.

This research was continued in 2017 to again assess the seed row fertilizer effects on canola, and this year spring wheat was replaced with lentils. The change to lentils instead of spring wheat was due to there being little to no adverse effect on the stands and yields of spring wheat observed in 2015 and 2016. Due to the increasing lentil acres grown, information on seed row effects is needed. The additional year of research was conducted on a medium-testing P soil a few km east of Lethbridge, AB. For canola, there was a minor observable decrease (9%) in stand establishment at all rates of P (20 through to 40 lb P₂O₅/A). However, even though the canola crop stand was somewhat decreased, it was compensated through growth by increasing stem branching to produce similar canola yields. There was a similar trend for lentils, with an 8 % reduction in crop stand on average for all of the P fertilizers applied in the seed row, but the yields were not adversely affected. This research shows that greater rates of seed row P can be tolerated, up to at least 30 lb P₂O₅/A, without significant adverse effects on yields.